There is a continual existing need for blood donors in order to meet the day to day hospital demand for blood. The collection of blood from donors is a critical function performed in all towns, cities and metropolitan areas as the need for fresh blood and plasma by hospitals never diminishes. Consequently, various blood collection centers have been established at permanent locations and mobile blood collection units are employed to service remote areas or to obtain blood from donors at specific high density locations, such as shopping centers, factories, office buildings, etc.
The process for collecting blood is a relatively simple process with respect to the donors"" participation. However, the means for testing, typing, storing and preserving the collected blood requires relatively sophisticated techniques and equipment to minimize loss from contamination or spoilage.
Normally, the blood is drawn from a donor through flexible tubing extending into a plastic blood collection bag. Once the bag is filled to a predetermined quantity/weight, the tubing must be sealed to prevent leakage and, more importantly, to prevent contamination and deterioration of the collected blood. After collection, the blood must be typed and tested under various criteria. To provide a representative supply of blood for these typing and testing purposes, a plurality of blood filled segments of the tubing are sealed from one another to provide a plurality of segreable sealed samples which are opened only for typing and testing purposes.
At most blood collection centers, such as those operated by the Red Cross, much of the manual labor is performed as charitable work by older persons. These persons often are physically handicapped by the natural processes of aging, by arthritis or by previous injuries. For those persons who perform the work of sealing segments of filled blood tubing, the operation of the equipment must require a minimum of effort, be easy to use after minimal instruction, and minimize operator fatigue. Furthermore, safeguards need to be employed to minimize splatter of blood from a burst segment coming in contact with an operator; furthermore, only the grounded, and not the positive, jaw may come in contact with an operator.
A desk mounted sealer, such as either of the sealers described in U.S. Pat. Nos. 4,186,292 and 4,529,859, both of which are assigned to the present assignee and incorporated herein by reference, is usable by an operator who is either seated or standing and it provides a line of sight for the operator in either position. Thereby, operator fatigue is diminished and accurate positioning of the liquid filled tubing to be automatically sealed is promoted. Through actuation of a tubing position sensing switch or a foot operated switch, a seal will be effected in the tubing placed intermediate a fixed jaw and a movable jaw thereby allowing the operator to use one or both hands to repetitively place and reposition the tubing intermediate the jaws. The housing for the sealer sealingly encloses the operative elements to preclude seepage of fluid thereinto from a burst liquid filled length of tubing. The shaft supporting the movable jaw and extending from within the housing is sealed through a wiping seal.
As particularly shown in the ""859 patent, the fixed jaw includes a vertical channel attendant the structure forming the seal to accommodate rapid drainage of fluid in the event the tubing should burst during formation of the seal. The drainage will be exterior of the unit and thereby prevent contamination of the mechanical and electrical components attendant the unit. Switch means actuated by interception and reflection of a light beam attendant the fixed jaw triggers the unit to effect a seal and thereby eliminate operator actuation of the unit. Furthermore, it is common for an operator to place a blood bag upon the tube sealing unit when the tubing therefrom is being sealed. Spoilage of the blood will result if the bag placed upon the unit is subjected to heat above normal body temperature. The heat produced by certain of the components within the unit as a result of generation of RF energy to effect the tubing seals is channeled by conduction to the bottom plate or to a finned heat exchanger exterior of the unit. Dissipation of heat from both the bottom plate and the heat exchanger is by convection. Because of such heat channeling, the top of the unit upon which blood bags are often placed is generally maintained at essentially ambient temperature and spoilage of the blood will not occur.
The bench top tubing sealer described and illustrated herein embodies several unique concepts summarized below. Any tubing sealer includes three primary component assemblies of solenoid assembly to actuate a movable jaw, electrical power supply and electrical circuitry for generating RF energy to be applied to a fixed jaw. Each of these assemblies generates heat which must be dissipated. To minimize heat transfer between the three components, three compartments are created by internal structure and a cover. Air flow is channeled through each of the compartments to draw off heat from critical surfaces and components and is exhausted through outlet ports in the base. Safety measures enacted in the United States and in countries foreign thereto require containment of spurious and unauthorized RF radiation within the tubing sealer, which is accomplished by metallic shielding and the air outlet ports are configured to prevent RF spurious and unauthorized radiation therethrough. By using the circuit board with surface mount technology for the electronic circuitry and an internally located heat sink, heat generation is managed and minimized; furthermore, the compactness afforded by surface mount technology reduces the size of the required circuit board and permits significant air volume for cooling purposes. The relatively massive movable sealing and grounded jaw will absorb heat from the tubing and be cooled by convection. By slanting the attached supporting movable shaft, flow of any fluid along the shaft will be away from the sealer to avoid internal contamination. Status and signaling lights may be mounted within a translucent face plate to eliminate fluid access therepast into the sealer. A pair of rods guides the movable jaw and maintains its alignment with the fixed ceramic/metal positive sealing jaw. A lever operated micro switch responsive to correct placement of tubing between the jaws actuates the circuitry to generate the RF energy used to heat the tubing clamped between the jaws. The fixed jaw is integrated into the face plate in a manner to prevent the operator from touching the fixed jaw and thereby prevent injury from RF burn; additionally the massive size of the movable jaw, in combination with a splash guard, restricts operator access to the fixed jaw.
It is therefore a primary object of the present invention to provide channeling of cooling air and eliminate heat build up within a bench top tubing sealer.
Another object of the present invention is to provide a bench top tubing sealer having segregated internal compartments for containing the major components and for controlling the flow of cooling air therethrough.
Another object of the present invention is to provide a bench top tubing sealer that restricts external radiation of spurious RF energy at unauthorized frequencies.
Yet another object of the present invention is to provide segregated compartments within a tubing sealer, each compartment being in fluid communication with a source of air flow for cooling purposes.
Still another object of the present invention is to provide exhaust ports for a bench top tubing sealer which preclude transmission of unauthorized frequencies of RF radiation therethrough.
Still another object of the present invention is to provide a bench top tubing sealer that will not radiate RF energy at frequencies that may interfere with other electrical equipment that may be in proximity.
A further object of the present invention is to provide a bench top tubing sealer with numerous safeguards against the possibility of intrusion into the bench top tubing sealer of blood from burst tubing.
A yet further object of the present invention is to provide an ergonomically shaped bench top tubing sealer to minimize operator fatigue and to protect the operator from RF burns.
A yet further object of the present invention is to provide a method for cooling the components of a bench top tubing sealer without compromising containment of spurious and unauthorized RF radiation.
A yet further object of the present invention is to provide a large mass movable grounded sealing jaw for a tubing sealer to absorb heat from the tubing being welded and to be cooled by convection through its large surface area.
These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.